#include "MyStdio.h"


#define FILE_MODE 0666


_FILE* _fopen(const char* filename, const char* flag)
{
    int way = 0;
    int fd = -1;
    if(strcmp(flag, "w") == 0)
    {
        way = (O_CREAT|O_WRONLY|O_TRUNC);
        fd = open(filename, way, FILE_MODE);
    }
    else if(strcmp(flag, "a") == 0)
    {
        way = (O_CREAT|O_WRONLY|O_APPEND);
        fd = open(filename, way, FILE_MODE);
    }
    else if(strcmp(flag, "r") == 0)
    {
        way = O_RDONLY;
        fd = open(filename, way);
    }
    else 
        return NULL;

    if(fd == -1)
        return NULL;

    _FILE* fp = (_FILE*)malloc(sizeof(_FILE));
    if(fp == NULL)
        return NULL;

    fp->fileno = fd;
    fp->flag = FLUSH_ALL;
    fp->out_pos=0;

    return fp;
}


int _fwrite(_FILE* fp, const char* msg, int len)
{
    memcpy(&fp->outbuffer[fp->out_pos], msg, len);
    fp->out_pos += len;

    if(fp->flag & FLUSH_NOW) 
    {
        write(fp->fileno, fp->outbuffer, fp->out_pos);
        fp->out_pos = 0;
    }
    else if(fp->flag & FLUSH_LINE) 
    {
        if(fp->outbuffer[fp->out_pos-1] == '\n')
        {
            write(fp->fileno, fp->outbuffer, fp->out_pos);
            fp->out_pos = 0;
        }
    }
    else if(fp->flag & FLUSH_ALL)
    {
        if(fp->out_pos == SIZE)
        {
            write(fp->fileno, fp->outbuffer, fp->out_pos);
            fp->out_pos = 0;
        }
    }

    return len;
}


void _fflush(_FILE* fp)
{
    if(fp->out_pos > 0)
    {
        write(fp->fileno, fp->outbuffer, fp->out_pos);
        fp->out_pos = 0;
    }
}


void _fclose(_FILE* fp)
{
    if(fp == NULL)
        return;

    _fflush(fp);
    close(fp->fileno);
    free(fp);
}
